www.xprgroup.com
6
5.2 CONNECTING BIOMETRIC READERS WHEN ALL THE CONTROLLERS HAVE TCP/IP COMMUNICATION
50 ohm
50 ohm
Jumper for
RS485 termination
TCP/IP
gnd
gnd
1 km max / 32 Units (EWS + Biometric Readers)
Stub
max. 5m
RS485
TCP/IP
Switch
50m
max.
50m
max.
50m
max.
•When all the controllers are connected via TCP/IP, then the RS485 network becomes local (from Reader 1 to the Controller then
to the Reader 2).
•Connect the readers directly to the Rs485 terminals in each controller.
•If the distance Reader-Controller is high (50meters) and if the communication with the reader can not be established, then
terminate the RS485 network by closing the jumper in the EWS Controller or as described in chapter 4.
NOTE: This is recommended configuration when you have multiple biometric readers in the same network.
In this configuration, NO TERMINATION resistors are required.
When all the controllers have TCP/IP communication the biometric readers are easily wired. When the controllers have RS485
communication, it is difficult to maintain the daisy chain of the RS485 network. Wiring the biometric readers in that formation
is a challenge. See the schematic diagram bellow.
5.3 RS485 TUNING
Rs485 Termination resistors:
- Terminate both ends of the line with 120 Ohm resistor. If end of line is EWS, use built in resistor (120 ohm) by closing
the jumper.
- If the communication is not established and stable, use the external resistors provided in the hardware kit.
When using CAT 5 compatible cable, in most of the cases, termination made with 50 Ohm external resistor or combination
of 50 Ohm external and termination resistor from the EWS (120 Ohm) should be the solution.
RS485
RS485
